Preheat the oven to 350°. In a small saucepan, combine the walnuts, sugar and water; bring to a boil, stirring, until the sugar dissolves. Cook over moderate heat, stirring, for 5 minutes. Using a slotted spoon, transfer the walnuts to a pie plate and sprinkle lightly with salt. Bake for 7 minutes, or until the nuts are fragrant and lightly caramelized. Let cool.